In hydraulic continuously variable transmissions, hydraulic pumps, hydraulic motors and the like, a thrust bearing is incorporated as a bearing. For example, in agricultural machines such as combine harvesters tractors, rice planting machines, and lawn mowers, there is a transition from a gear mission type to the hydraulic continuously variable transmission. In such a hydraulic continuously variable transmission, a thrust bearing is adopted in a portion that receives the pressure of the piston, when converting rotational power of a shaft into hydraulic pressure, or when converting hydraulic pressure into the rotational power of the shaft (for example, see Patent Document 1).